Various embodiments of the present disclosure relate to an antenna device.
Recently, wireless communication techniques have been implemented by using various methods, such as Wireless Local Area Network (W-LAN) represented by Wi-Fi technique, Bluetooth, and near field communication (NFC), in addition to a commercial mobile communication network connection. Mobile communication services were initiated from a first generation mobile communication service centered on voice communication, and have gradually been developed to a super-high speed and large capacity service (e.g., a high quality video streaming service). It is expected that the next generation mobile communication service, which is to be commercially available in the future, will be provided through an ultra-high frequency band of dozens of GHz or more.
As communication standards, such as W-LAN or Bluetooth, are evolving, electronic devices, such as mobile communication terminals, are equipped with antenna devices to accommodate operation in various different frequency bands. For example, the 4th generation mobile communication services are operated in a frequency band of, e.g., 700 MHz, 1.8 GHz, or 2.1 GHz. Wi-Fi is operated in a frequency band of 2.4 GHz or 5 GHz which may differ slightly depending on protocols, and Bluetooth is operated in a frequency band of 2.45 GHz.
In order to provide a stable service quality in a commercial wireless communication network, an antenna device should satisfy a high gain and a wide beam coverage. The next generation mobile communication service will be provided through an ultra-high frequency band of dozens of GHz or more (e.g., a frequency band in a range of about 30 GHz to 300 GHz and having a resonance frequency wave length in a range of about 1 mm to 10 mm). Such ultra-high frequency band may require a higher performance than that of the antennas used in former commercial mobile communication services.
In general, as the operation frequency band increases, the rectilinear advancing property of radio waves may be improved and a loss due to the transmission distance may increase. In addition, as the rectilinear advancing property of radio waves is high, the attenuation or reflection loss of a signal power by an obstacle (building or geographic feature) may increase. Accordingly, in a communication system using a high operation frequency, local shadow regions may appear all over a built-up area or an indoor space of, for example, a vehicle or a building. Even in the indoor space of the same building, radio wave environments may be greatly different from each other depending on divided spaces. Accordingly, the communication system, which uses a high operation frequency band, may require a technique for delivering radio waves to a shadow region.